1. Field of the Invention
The present invention relates to a system which boots an operation system over a network.
2. Description of the Related Art
A system (hereinafter referred to as a “network boot system”) which boots an operating system (hereinafter referred to as an “OS”) over a network has received attention in recent years. The system is composed of at least one network boot server (I/O server) and a plurality of client terminals connected over a network. Several types of system configurations are available as candidates for the system. The most common one is such that all programs and data such as an OS and application software operating on a client terminal are stored as image data in a storage device (e.g., a hard disk) on the server side and such that the OS is loaded onto the client terminal over a network when the client terminal is booted.
If a network boot system has a mechanism in which a plurality of client terminals share a storage device on the server side, each client terminal may be diskless, i.e., need not have a hard disk. The network boot system has the advantage of being able to manage all data including an OS of each client terminal in a centralized manner on the server side. The network boot system is thus suitable for a system in which a large number of client terminals operate.
Since an OS and application software are executed using a CPU and a physical memory of each client terminal, the network boot system also has the advantage of being able to maximize the performance of each client terminal and minimize server loads.
If n clients simultaneously access a server in this system, the throughput of the server simply decreases to 1/n. Loads produced by individual clients are temporally distributed in normal use, and the decrease does not pose a serious problem. For this reason, even if the number of client terminals to be simultaneously used increases, the network boot system in normal use delivers performance which is by no means inferior to, e.g., a general (not network boot) stand-alone computer system which boots its operating system by itself. Note that examples of a document related to the related art of the present invention include Japanese Patent Laid-Open No. 2005-149334.